Debian Corefiles

Posted in HowTo, Informational, Security on February 16th, 2009 by termina

If you have any issues with programs segfaulting, it can be useful to allow coredumps in order to see what happened.

You first have to allow coredumps

vi /etc/security/limits.conf

*  –  core  100000

@users  –  core  0

core is measured in kbytes, and core files can be fairly large (the simple script below generates a 350kb file).  Do not set this to unlimited for regular users!

echo 1 > /proc/sys/kernel/core_uses_pid

mkdir /tmp/core

echo “/tmp/core/dump” > /proc/sys/kernel/core_pattern

ulimit -c 100000

To test it let’s create a script that will cause a coredump.

vi core_dump.sh

#!/bin/bash
#core_dump.sh
kill -s $$
#end

chmod +x core_dump.sh
./core_dump.sh

ls /tmp/cores

dump.14594 core_dump.sh

To view the corefile, you need gdb.

apt-get install gdb

gdb -c dump.13594